Metallurgical furnace having a stirring winding



L. DREYFUS Jan. 5, 1954 2,665,319

I METALLURGICAL FURNACE HAVING A STIRRING WINDING 2 Sheets-Sheet l Filed May 9, 1950 Aufl-1ra .14.

ATTORNEY l.. 'DREYFUS 2,665,319 METALLURGICAL FURNACE HAVING A STIRRING WINDING Jan. 5, 1954 2 Sheets-Sheet 2 Filed May 9, 1950 INVENTOR 00u/76 aPfy/'as ATTORNEY Patented Jan. 5, 1954 2,665,319 ME'rtLJRGIoAL YFURNACE V'NG A STIRRING WINDING Ludwig Dreyfus,l Vasteras', Sweden,` assignor to Alhnanna. Svenska Elektriska Aktiebolaget,

Vasteras, Sweden,

a corporation of Sweden Application May 9, 1950, Serial No. 160,861 Claims priority, application Sweden-May 24, 1949 8 Claims. l

It is known to provide metallurgical furnaces, as for instance arcl furnaces, open hearth furnaces or so-called mixers, with a polyphase winding adjacent the lower portion of the furnaces, for instance beneath its bottom, said winding being` fed by current of a low frequency,v invlarge furnaces generally lower than one cycle per second, and serving to produce by induction forces in the molten contents of the furnace (the bath). Said forces act in a direction essentially parallel to that of' the phase sequence and cause a motion in the bath,vwhich may accelerate metallurgical reactions therein or in some cases, as in mixers, only contribute tov an equalisation of the temperature. Experiencer has however proved, that in the case of such stirringof the bath it may sometimes be advisable, to change from time to time the directions ofthe movement, andthe present invention has for its object to providev such an arrangement ofl the stirring winding as to make this possible.

The most simple way of changing the direction of movement is to reverse the phase sequence in the polyphase, generally two-phase, winding, for instance by changing the connections between the winding' and it's source of current.` If this source, as is generally the case at the low frequency employed, consists of one or more commutating alternating current machines, the change of phase sequencev also may be'effected by changing the brush position on-oneormore machines. Sometimes it may, however, be advisable"to`vary the direction of movement through a smaller angle than 180, and for this purpose the' mutual angular position betweenr the winding and the furnace body may be altered. The windingwith its iron core and other accessories-may for instance be suspended beneath the furnacel body in such manner as to make thef'ormer rotatable through-a certain angle with respect to the `latter about a vertical axis. In many cases, especially in arc furnaces with electrodesV mounted above the furnace bath, the furnace body proper' 'is made angularly displaceable with respect to its support for equalising the corrosion of the furnace wall which always appears near the electrodes. In such cases, the stirring coil can be mounted in a fixed position in the support of the furnace, whereby it will occupy different angular positions with respect to the movable furnace body.

Four forms of the invention are diagrammatically illustrated in Figs. 1-4 of the accompanying drawing. All the gures show the principal part of the furnace in a vertical section, although on 2 a smaller scale in Figs. 1 and 2 than in Figs. 3 and-4.

In all the figures, the furnace body is designated by I, its cover by 2, and the electrodes penetrating through said cover by 3. The electrodes are not affected by the invention, and their accessories, as supporting devices, regulating means and current supply conductors, are therefore not shown.. The furnace body has a tapping spout 4 and an opening 5 for charging and for removing slag. It is supported by a rocking base 6 so as to be easily tilted for tapping. The stirring winding, protected 'by a shell I0, which is partly broken awayabove thedash and dotted line-to show the winding coils, is in all the figures shown as two-phase, one of its phases II having terminals IIl, I I11 and the other phase I2 having terminals |21, i211.

In Fig. l, the furnace body is supposed to be stationary with respect to its base 6, and the winding is directly supported by the furnace. The Winding is fed from two brush sets on a commutating generator I5, there being interposed between the terminals Ill, lill of one phase and the corresponding brush set a double reversing switch I6. When the later is in its right position, asshown, the left terminal I I1 is connected to the top brush and the right terminal to the bottom brush. By reversing the switch I6, the currentdirection of the winding II and thereby the direction of the stirring movement caused by the-two-phase winding is reversed.

In Fig. 2, the generator I5 feeding the twophase-winding II, .2 has an angularly displaceable frame I'I supporting the one set of brushes, and by turning this frame through electrical degrees, the phase sequence between the winding phases can be reversed.

In Fig. 3, which shows the furnace on a larger scale so as to clearly show` certain mechanical details thereof, the base 6 supports the furnace indirectly by-rneans of rollers l rotatably mounted in the base and a circular rail 8 resting thereon so as to be rotated with the furnace. The rotation can be effected by means of a motor 9 with a reduction gear. During the said rotation, the furnace roof may be kept in a raised position so as not to partake in the rotation. Such an arrangement is known in principle and has for its purpose to prevent a too strong corrosion of the furnace wall in the neighborhood of the electrodes by changing their relative position with respect to the furnace body.

In Fig. 3, a furnace body angularly displaceable with respect to its base is combined with a stirring Winding which is stationary with respect to the base. The protective shell I of the said winding is partly broken away, as in Figs. 1 and 2, to show the winding phases I I and I2 which are connected to the two-phase generator I5 In this case, it is not necessary to change the connections between the winding and the generator, although it may be done also in combination with the angular displacement.

In Fig. 4, the furnace body I is solidly supported by the rocking base 6, and the connection between these parts is therefore not shown in detail. On the other hand, the stirring winding II, I2 with its protective shell I0 rests on an annular bar IS, which rests in its turn on a set of rollers i9, which may be rotated by a motor 20 with a gearing so as to turn the stirring winding with respect to the furnace body. The generator and the conductors between the same andthe winding are illustrated and designated in the same manner as in Fig. 1.

Instead of using one two-phase or generally polyphase generator, a corresponding number of single-phase generators may be employed. The modifications of the illustrated diagrams incurred in such case are obvious.

The term interlinked, as used in the claims, means that the coil sides of one phase, such as I I, alternate with the coil sides of the other phase, such as I2. Such coil sides are shown in my prior Patents 2,513,082 and 2,256,518.

' I claim as my invention:

1. A metallurgical furnace comprising a normally stationary receptacle for a molten content, a polyphase winding mounted beneath and across the bottom of said receptacle and having its phases interlinked, means for feeding low frequency current through said winding to induce electro-dynamical forces in said content, and means for altering the direction of said forces relatively to said receptacle.

2. A metallurgical furnace comprising a normally stationary receptacle for a molten content, a polyphase winding mounted beneath and across the bottom of said receptacle and having its phases interlinked, means for feeding a low frequency current through said winding to induce electro-dynamical forces in said content, and means for temporarily reversing the phase sequence of the current fed to said winding.

3. A metallurgical furnace comprising a normally stationary receptacle for a molten content, a two phasewinding mounted beneath and across the bottom of said receptacle and having its phases interlinked, means for feeding a low frequency two phase current through said winding to induce electro-dynamical forces in said content, and means for temporarily reversing the current in one phase of said winding.

4. A metallurgical furnace comprising a, normally stationary receptacle for a molten content, a polyphase Winding mounted beneath and across the bottom of said receptacle and having its phases interlinked, a polyphase current source for feeding low frequency current through said winding, and means for changing the connections between said current source and said winding to reverse the phase sequence in said winding.

5. A metallurgical furnace comprising a normally stationary receptacle for a molten content, a polyphase winding mounted beneath and across the bottom of said receptacle and having its phases interlinked, a polyphase commutating generator having for each phase sets of brushes for feeding current to said winding, and means for displacing-at least one set of brushes for reversing the phase sequence of said current.

6. A metallurgical furnace comprising a normally stationary receptacle for a molten content, a polyphase winding mounted beneath and across theA bottom of said receptacle and having its phases interlinked, means for feeding low frequency current through said winding to induce electro-dynamical forces in said content, and means for altering the relative angular position of said winding and said receptacle.

7. A metallurgical furnace comprising a normally stationary receptacle for a molten content, a base supporting said receptacle, means for angularly displacing said receptacle relatively to said base, a polyphase winding mounted on said base adjacent to the bottom of said receptacle, said winding having its phases interlinked, and means for feeding low frequency polyphase current through said windings.

8. A metallurgical furnace comprising a normally stationary receptacle for a molten content, a'polyphase winding supported by said receptacle beneath and across the bottom thereof so as to be angularly displaceable with respect thereto about a vertical axis, said winding having its phases interlinked, means for feeding low frequency current through said winding to induce electro-dynamical forces in said content, and means for turning said winding with respect to said receptacle.

LUDWIG DREYFUS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 873,861 Holmgren Dec. 17, 1907 1,068,558 Bally July 29, 1913 1,983,242 Rohn Dec. 4, 1934 2,018,885 Ferguson Oct. 29, 1935 2,099,593 Bender et al Nov. 16, 1937 2,144,886 Mars et al Jan. 24, 1939 2,181,921 Schlup Dec. 5, 1939 2,191,377 Gallusser Feb. 20, 1940 2,198,304 Cornelius Apr. 23, 1940 2,224,982 Morin Dec. 17, 1940 2,256,518 Dreyfus Sept. 23, 1941 2,363,582 Gerber et al Nov. 28, 1944 2,513,082 Dreyfus June 27, 1950 2,538,979 Parage Jan. 23, 1951 

